8 



we each have a duty to general biology, which furnishes the basis for 

 all economic work, and that while we choose subjects of immediate 

 economic importance, we should not neglect such underlying problems 

 as shall perfect the fundamental knowledge of our science. Much of 

 the work done must necessarily be for immediate results, to devise 

 ways and means for control of pests that are demanding notice from 

 the cultivator, but as we build upon the work of the past, so we must 

 contribute our share to the foundation for the future edifice. 



It is hardly necessary here to call attention to the importance of life- 

 history work as the essential basis for economic entomology, and if it 

 were. I could refer you to the plea for such study so ably presented by 

 my predecessors. It should not be forgotten, however, that this means 

 more than the 'mere breeding of the different stages of an insect, for 

 beyond them and dependent upon them are many deeper biological 

 problems, the importance of which in economic work we can probably 

 only slightly appreciate at the present time. The general problems of 

 heredity, variation, dimorphism, mimicry, parasitism, influence of envi- 

 ronment, distribution, etc., may seem at first to belong only to pure 

 science, but I believe a closer examination will show that in these and 

 other fundamental questions we have some problems of the utmost 

 significance in the application of science to economy, and that from 

 simple duty we should contribute such facts as we can toward their 

 elucidation. 



It has been the fashion to think that the solution of such questions 

 is most easily sought among the simpler forms of marine life, but many 

 fruitful fields are certainly still open for the student of insect life. 

 Problems of distribution are of fundamental importance and can not 

 be too thoroughly studied, even though the immediate economic returns 

 seem slight. Undoubtedly there are fundamental factors affecting the 

 distribution of insects which, when fully known, will be of immense 

 value in determining methods of control, necessities of quarantine, etc. 

 While certain species of insects appear to override all barriers, I believe 

 we will find that m the main they are dependent on certain conditions 

 of climate and food plant, and that their natural limitations may be 

 defined with reasonable accuracy. The value of such definition in 

 determination of crops is evident at a glance. 



Determination of limits in food plant is another and closely related 

 line in which accurate record and extended, though not necessarily con- 

 tinuous, observation is essential. To know the limits of food plant for 

 any species is to have a most powerful weapon of control, as for instance 

 in the treatment of corn-root worm. 



Of great importance also is the recognition of alternations in food 

 plant and habit, and careful determinations in this direction have not 

 only high scientific interest, but great economic value. The phorodon 

 of hop and plum furnishes a striking example of the utility of such 

 knowledge. 



